Light Magenta/Light Cyan Pint Heads Last Only After One Print Job

On a Latex 370 printer the Light Magenta/Light Cyan doesn't last long. Physically there is nothing wrong with it. It prints fine with no missing nozzles. It just seams to starve or not lay down as much as it should. I always have to change it out and it prints correctly after that. But it prints correctly after only about 10 ft of material then is starts to fade away. If I do a color calibration it prints fine with no banding but it still no longer prints correctly. I have to replace it again. Usually greys should be grey but it comes out yellowish.

All settings are the same. Intermediate cartridges are full. Print head clean was done. Color calibration done. I wasted about 10 LM/LC print heads. One for every job.

Hi @apcguam,

My recommendation would be to check and clean the PHs, then print a plot of 36x12 inches in Magenta. If you are still having issues, please contact HP support.

What is the status of each of the light inks (are they possibly expired)? You can get this information from the front panel of the printer, under the inks menu.

I would actually look at a couple things. If you have had several of these heads that have failed under very short use, you may want to determine the following:

1. Ensure you inks are full, not near expiration and that you have re-seated them.
2. Have you used the deionized water method to clean the head prior to after the head was deemed a problem, drip 3 drops and wait10 seconds, repeating 3 times on the face of the nozzles, ten blot the nozzles against a lint free cloth for 3 - 6 seconds, allowing it to wick out a good amount of ink from the head prior to wiping it off and installing it.
3. Have you looked at the drop nozzle detection for the head. to see if cleaning it has resolved the nozzle deficiencies.
4. Have you removed and looked at the Maintenance Cartridge, cleaned the wiper and rollers with luke warm water on a clean cloth for the colour and the OP channels, DO NOT mix the cloths, use a new clean area when cleaning it pr a separate cloth. Inspect the maintenance shelf and make sure there is no sign of leak, or contamination of the OP head/channel.
5. If OP drops are detected, remove that head and inspect it, it is possible with damage that it can contaminate other heads if leaking. 6.Print the Colour Cal, to ensure the Lt Cyan Lt Mag head is printing correctly. You could try printing magenta and cyan at a 25% fill to have the printer use that head, print a patch 36x12 inches to determine if there is a deficiency.
6. If under warranty call the support channel for consumables and have them walk you through some troubleshooting to see if there is a root cause that tey can identify.

I am having the identical problem on my HP335. Has anyone found a solution to this issue?? It's getting very frustrating, not to mention extremely expensive in wasted prints. I've tried everything i can think of with no solution. I have never passed the 36ml mark on a Lt.Cyan/Lt.Magenta head to date. All of my mid-tones and greys take a big color shift. Replacing the printhead solves the problem every time, but there are no visible issues with the printhead. All nozzles are firing, all test plots look perfect. Someone suggested doing a "force drop test" to ensure the head is okay. All values come back low, under 15 to be precise.

Inks are up to date and not expired in the printer. This issue doesn't seem to make any sense. Other printheads in the printer surpass the 2500ml mark with no issues.

As mentioned is a previous post, it almost seems like the Lt.Magenta is starving for ink. I'm not sure how the system pressurizes the ink system or delivers ink to the head. Is there a way to force the printer to do a prime or some other routine to purge possible air in the lines? I'm really stumped as to why this happens only after a few feet of printing but comes right back to a perfect print job by putting in a new head.

This printer is close to 1-year old!!!

UPDATE - PROBLEM RESOLVED

So, where do I start? Well, I've been researching this issue and had not come up with much in the way of a solution. Even talks with HP technical support offered no fix. In fact, they wanted to send a technician to replace all the "towers" in my print carriage. These are basically the electronics that control the print heads. At a cost starting at $2,000 for the repair, I was certain this would not resolve the issue. It made no sense that this would be the issue and I was not prepared to shell out that kind of money on a repair that I felt was not necessary. Although the technician assured me this would fix the problem, I had my doubts, and I'll tell you why.

Using a little bit of logic, and the fact that I was a computer technician for many years (working on both PC's and inkjet/laser printers) I was able to formulate a hypothesis that there were not actually ANY hardware issues at all. This includes all the "damaged" print heads.

Since all brand new print heads come loaded with approximately 30ml of ink, one would have to wonder why every single print head would "fail" after only a short use (approximately 25-35ml). Each time a LC/LM print head is replaced, color goes back to normal. Once the ink in the head is depleted, color shifts once again to greenish color. Running with a logical hypothesis, I decided that the fault was in the ink. Seeing how LC/LM are the two least used inks in the printer, I had the following thought. What if the ink in the cartridges started to settle out and the printer was pulling pigment deficient liquid?? I replaced both the LC and LM cartridges with new ones. I estimated that the amount of ink in the lines to the print heads to be approximately 100ml. I created a print file comprised of a large block filled with 40% Magenta. This would allow me to print only Light Magenta ink and not waste other valuable ink. The size of the block was 50"x36". I left the so called "bad" print head in the machine and proceeded to print. I made sure to do a head clean (on the LC/LM head only) before each print run. Paying careful attention to ink consumption on the "inks" screen on the printer, I ran the test print over and over for a total of 6-8 times. (if you are worried about wasting media, you can roll back the vinyl and print over each previous test block) The goal is to use up all the ink in the lines so fresh ink will reach the print head. Not to my surprise, I ran a test print of a Pantone chart comprised of all the shades of grey, including all the warm and cool grey colors.

Bingo!! Pantone color chart printed out beautifully, and from a head that HP deemed "faulty".

I can't stress the following point enough, SHAKE YOUR INK CARTRIDGES REGULARLY

It's been two weeks now and I have had absolutely no issues with color. If i had gone ahead with the $2,000 unnecessary repair, the technician would also have been correct. It would have solved the problem, simply because the procedure would have required the ink in the lines to be purged.

Hopefully this will help others in the future avoid unnecessary costly repairs, not to mention the fact that HP charges you for phone support.

Do yourself a favor, setup a monthly "replace ink" task to take out all your cartridges and shake them as part of your regular maintenance routine.

Sorry. Maybe we should close this. I just replaced the little tubes where the print head pin goes in. Those things leak at the connection. So instead of replacing the whole tube set just replace that little part.

#6 I think this explanation makes the most sense to me. Thank you. I will now add this ritual monthly. "I'm shakin' it boss" - Cool Hand Luke.

#6 said

It's been two weeks now and I have had absolutely no issues with color. If i had gone ahead with the $2,000 unnecessary repair, the technician would also have been correct. It would have solved the problem, simply because the procedure would have required the ink in the lines to be purged.

It's been about a year since this post. Do you have any additional follow-ups? I'm printing a grey colour on a LTX 110 and it's printing purple-mauve colour.

#9 Run a calibration and see if the LM and/or LC look crappy on the solid blocks. If they do, replace the ink OR AT Least take them out and shake them well. Then you've gotta print big solid blocks of those colors (either or both if they both look bad) to get the bad ink out of the lines. After you print your block take a look in the printer's web server to see how much ink it used. I have no idea how much ink is in a 110's lines - I read one guy who said there was about 30ml in a 315 and another guy who guessed 100ml in a 335. That seems really high to me but I don't really know. Anyway, see how much you used and do some division to figure out how many times you need to run the block. To save material you can retract it and print it over itself. After you run the blocks try another calibration and see if they look better. Then reprint your grey and see if it worked!

IMPORTANT CAVEAT 1 - this is all assuming you're running the right profile, you are calibrated, and you know you are for sure sending a neutral gray.

IMPORTANT CAVEAT 2 - I have read this method both up there in reply #6 and at signs101.com and I am in the middle of doing it myself. I have NOT completed it yet so I don't know for sure if it even solves my problem, let alone yours! :-D

#10 Thanks for the tips and I am diving further into this this week and over the Christmas slow down we may (or may not) see. In addition to the grey printing mauve I noticed on a print job last week that my yellow is printing very light (weak). I had a beige/brown area that was printing more pinkish. So far I've replaced the yellow ink cartridge and have confirmed the that the two Y/M printheads are firing. I'm going to make up some print tests to 'purge' the yellow line as you have suggested. Next step may be to order two new printheads, even though the two in use appear to be firing on most nozzels.